Horizontal freezing plate for a twin contact freezer



F. RlcHELLl 3,234,755

HORIZONTAL FREEZING PLATE `FOR A TWIN CONTACT FREEZER Feb. l5, 1966 2 Sheets-Sheet 1 Filed March 9, 1964 'llllllrllvlv INVENTOR.

FEDER/co RICHEL 1./

/QrraR/v ys F. RlcHELLa 3,234,755

HORIZONTAL FREEZING PLATE FOR A TWIN CONTACT FREEZER Feb. l5, T966 2 Sheets-Shea?l 2 Filed March 9, 1964 TTORNEVS United States Patent 3,234,755 HORIZONTAL FREEZING PLATE FOR A TWIN CONTACT FREEZER Federico Richelli, Via Bolzano 31, Milan, Italy Filed Mar. 9, 1964, Ser. No. 350,345 Claims. (Cl. 62-525) This invention concerns a horizontal freezing plate for a twin contact freezer.

There are already known types of horizontal freezing plates essentially composed by a pipe coil-pressed or welded-which may be placed between two end sheets, or said pipe coil is made to contact directly the product to be frozen, as it lacks any intermediate elements for cold transfer. In all cases, said freezing plates show some defects an-d shortcomings, both from the structural` and functional viewpoint, i.e. of the thermal efficiency.

Actually, for the case of pipe coils used along with a pair of sheets, as the former are tubular elements having -a square or rectangular cross section, there happen to be many voids between pipe coils :and flat sheets, so that heat transfer in said voids is greatly hampered owing to the presence itself of intermediate elements between refrigerating body and the one to be refrigerated.

For the case of plates with in-built pipe coils, up to now it has been impossible to balance beyond a certain level the cold transfer ratio between the upper outside surface of the coil and the lower outside one of the same.

The main functional defect bearing upon said thermal efciency, is due to the fact that the refrigerating fluid which evaporates within the coil, does not completely fill with liquid the cross section, in order to allow for the exhaust of the gas being produced during the evaporation; one therefore is not in the position of obtaining the same eiciency on the twin surfaces of the freezing plate.

Particularly, as one has to deal with elements having horizontal pipe coils which are to cool on both faces, being given a pair of elements enclosing a body, the upper plates surface will contain the refrigerating liquid directly in its lower part, i.e. in contact with the underlying body, which is to be refrigerated, while the pipe coil of the lower element shall contain the liquid in the lower part of its surface, therefore not in contact with the superimposed body, to be refrigerated. Therefore the efficiency of the lower element shall be much lower than the upper ones.

A first scope of this invention is to obviate the above referred to defects through the use of a freezing plate which, besides having a better thermal eiciency owing to the elimination of intermediate walls, is mechanically stronger and much smaller than known types even having the same rating of thermal transfer.

Another scope of the invention is the one of shaping the coils path in such a way as to allow for an adequate circulating speed for the refrigerating iluid, thus further improving the efficiency.

These and other scopes are obtained by the horizontal freezing plate for twin contact freezer, built according to this invention, which is essentially characterized in that it comprises groups of rectangular cross section tubular elements, horizontally disposed and mutually approached along their minor sides, which are connected in parallel between two manifolds, respectfully for intake and exhaust action, in such a way as to obtain the same number of pipe coil circuits where the evaporating i cooling iluid lflows, as well as to form-as a unit-a continuous plate the twin surfaces of which are flat, each of said elements being equipped, inside, with diverting means for the evaporating flow of cooling fluid, said means being disposed in such a way as to force said evaporating ow of cooling uid to lap the `bottom sur- 3,234,755y Patented Feb. 15, 1966 a ICC face as well as the opposed one of each of said tubular elements.

In another embodiment for the rectangular cross sectioned tubular elements, the diverting means of the evaporating flow of cooling fluid, provided inside said tubular elements, are made out with a thin sheet running in parallel to the twin main surfaces, from which sheet have been cut several openings with corresponding diverting tabs which have an up-trend along the direction of the evaporating flow of cooling fluid, starting from their connecting end, in such a way as to modify the said tluids path and force the same to pass through said openings, along said tabs, as well as to lap also the upper part of the tubular surface, which otherwise would remain untouched by said fluid.

The plate according to this invention rnay be advan tageously obtained through welding into groups of the various tubular elements, each group makes up a circulating system of the cooling fluid and all groups are later put in parallel, being con-nected by manifolds, themselves built as above i.e. with pipes of rectangular cross section.

The invention shall now be better described with reference to an embodiment, being given only as an eX- ample and as shown in the enclosed drawings, in which:

FIG. 1 shows in plan a plate according to this invention, for claritys sake, there have been omitted the diverting means Within the tubular elements composing the whole plate;

FIG. 2 shows the transversal cross section of same, along line 2--2 of FIG. l;

FIG. 3 shows in longitudinal and horizontal cross section a detail concerning a tubular element without the typical diverting means being located within the same and FIGS. 4, 5 and 6 show respectively a cross section plan, an elevation and a transversal cross section of a length of tubular element equipped, in its inside, with the typical diverting means.

With reference to the enclosed drawings (FIGS. l and 2), with A1, A2, A3 there are shown (FIG. l), three refrigerating groups forming the plate, put in parallel by the manifolds B1 and B2, B1 being connected with the C1 delivery pipe, while B2 is connected with the C2 return pipe. Each group A is formed by tive tubular elements, having-as already said-a rectangular cross section, preferably flattened, for obvious reasons of thermal eiciency and as allowed by the speed of the refrigerating uid; said fluid goes through each group following the pipe coils path, as shown by arrows f, entering from manifold B1 (arrows f1) and going out into manifold B2 (arrows f2).

To obtain this, it is necessary that, beyond the thermal, actuating fall between B1 and B2, there be an entrance (D1, D2, D3) and an exit (E1, E2, E3) for each group; i.e. the first and the fifth element 1 have their end sections open and respectively communicating with the B1 intake and the B2 exhaust manifolds, which are also provided with corresponding ducts. All other elements, as well as the two last remaining ends of said elements, are closed (for instance by the walls of the manifold upon which they are welded) but they have side openings 2a and 2b brought together reciprocally, in order to allow for the circulation along the arrows f.

From the structural viewpoint, the rectangular elements 1, which exist in each refrigerating group A1, may be made out with bent and welded sheets or with drawn pipes; the mutual connection itself takes place through welding, both between the 1 elements and between each group and the B1 and B2 manifolds, themselves obtained in the same way.

The side openings 2a and 2b, endly shown by each tubular element, are well visible in FIG. 3.

All elements-pipes 1 and manifolds B1 and BT-are equipped internally with the said, typical diverting means N shown in FIGS. 4, 5 and 6, splitting them longitudinally into two chambers 6 and 7, intercommunicating (FIG. 6).

, Said diverting, means comprises a thin sheet 5 equipped with tabs or swells 5a made out by appendixes formed through a suitable slitting operation, so obtaining the relevant openings 5c upon said thin sheet 5, said swells 5a being slantwise directed with reference to the plan of the thin sheet itself. Said swells 5a are, with reference to said plan, at an angle selected according to the e liquids speed, the level of which does not touch the cross sections top.

Said thin sheet 5 is also equipped with wings 5b, upwardly directed, in order to keep the sheet apart from the upper surface of the tube, in such a way as to obtain a cavity 6 for allowingy the free passage of the evaporating liquid.

Once disposed the thin sheet 5 with its appendixes 5a as in FIG. 5, i.e. in parallel relationship with both major faces of the tubular element, while the appendixes or tabs 5a are springing `and downwise directed towards the flow, said tabs will tend to raise the evaporating cool ing fluid, forcing it to lap also the surface 1a (being opposed to the bottom surface 1b), through the passage 5c. Therefore the heat transfer shall take place directly also through said surface 1a, with the efciencys advantages already explained.

Lastly, both for the provision of said diverting means and for the rectangular cross section of the tubes, which allow to eliminate in the same time both the intermediate plates and the dead spaces between pipes and plates, or also between tubes and objects to be refrigerated, one may so obtain a great augmentation of the thermal efficiency.

The actual possibility of running at a high circulating speed of the refrigerating fluid, which as already said, considerably improves the effect of the diverting means, is another positive factor with reference to the thermal efliciency of the upper surface, so that the plate according to this invention is actually capable of a quick freezing effect.

What is claimed as new and desired to be secured by Letters Patent is as follows:

1. A horizontal twin contact freezing plate having an upper continuous surface and a lower continuous surface, said lower surface being parallel to and coextensive with said upper surface, said plate including an intake manifold for admitting cooling fluid to be evaporated and an exhaust manifold, said exhaust manifold being parallel to said intake manifold, several groups of parallel tubular elements spanning the space between the intake and exhaust manifolds, each tubular element being of like rectangular hollow cross-section and consisting of horizontal plane upper and lower walls and vertical side walls, the side walls of adjacent elements in each group being in abutting intersecured relationship and the side walls of the outermost elements of adjacent groups being in abutting intersecured relationship, the upper walls of all the elements lying in a single horizontal plane and constituting the continuous upper surface of the plate, the lower walls of all the elements lying in another single horizontal plane and constituting the continuous lower surface of the plate, there being the same odd number of tubular elements in each group, means securing the ends of the tubular elements to the manifolds, means forming a passageway between the intake manifold and the adjacent end of an outermost element of each group, means forming a passageway between the exhaust manifold and the adjacent end of the other outermost element of each group, means forming passageways between alternate ends of elements of each group so that the elements of each group are connected in series and in a serpentine arrangement that passes evaporating cooling fluid from the intake manifold to the exhaust manifold and so that the groups are connected in parallel between said manifolds, and within each tubular element a diverting means forcing some of the evaporating cooling fluid that flows along the lower wall of the element Ito be elevated to flow along the Lipper wall of the element.

2. A freezing plate as set 'forth in claim 1 wherein each diverting. means includes many tabs, each sloping upwardly and in the direction of flow of the cooling fluid from a lower end adjacent the lower wall of the tubular e-lement in which the diverting means is located to an upper end near but spaced from the upper wall of said tubular element.

3. A freezing plate as set yforth in claim 1 wherein each diverting means includes -a thin sheet parallel to the upper and lo-wer walls of the `tubular element in which the diverting means is located, said sheet being spaced from both said Walls and dividing said element into two separate longitudinal chambers, tabs formed from 4said sheet, each said tab sloping upwardly and in the direction of flow of the cooling iluid from a lower end adjacent the lower wall of said tubular element to an upper end integral with the sheet and defining an opening left by forcing the tab out of the plane of the sheet whereby cooling fluid flowing along the lower wall rof the element in the lower chamber is rai-sed -by the tabs through the openings in the sheet onto the upper surface of the sheet in the upper chamber where the uid ows' in contact with the upper wall of the tubular element..

4. A freezing plate as set forth in claim 3 wherein the width of Athe sheet is the same as the width of the" tubular element.

5. A freezing plate as set forth in claim 3 wherein the sheet is closer to the upper wall of the tubular element than it is to the lower wal-l of the rtubular element.

6. A freezing plate as set forth in claim` 3 wherein the sheet includes upwardly extending win-gs engaging the upper wall off the tubular element to locate the sheet in a defini-te position with respect to the upper and lower walls of the tubular element.

'7. A freezing plate as set forth in claim 1 wherein the tubular elements are secured to the manifolds by welding and wherein abutting side Walls of the tu'bular elements are secured to one another by welding so that the elements and manifolds constitute a unitary structure.

8. A freezing plate as set forth in claim 7 wherein the rectangular hollow cross-section of the 4tubular elements is oblong with the major dimensions in the upper and lower surfaces of the plate and the minor dimensions in the side walls of the tubular elements.

9. A horizontal twin contact freezing plate having an upper continuous surface and a lower continuous surface, said lower surface being parallel to and coextensive with said upper surface, said plate including an intake manifold `for admitting cooling fluid to be evaporated and an exhaust manifold, said exhaust manifold being parallel to said intake manifold, several groups of parallel tubular elements spanning the space between the intake and exhaust manifolds, each tubular element being of like rectangular hollow cross-section and consisting of horizontal plane upper and lower walls and vertical side walls, the side walls of adjacent elements in each group being in abutting intersecured relationship and the side Awalls of the outermost elements 'of adjacent groups being in abutting intersecured relationship, the upper walls of all the elements lying in a single horizontal plane and constituting the continuous upper surface of the plate, the lower walls of all the elements lying in another single horizontal plane and constituting the continuous lower surface of the plate, there being the same odd number olf tubular ele-ments in each group,l means securing the ends of t-he tubular elements to the manifolds, means forming a passageway between thel intake manifold and the adjacent end of an outermost element of each group, means forming a passageway between the exhaust manifold and the adjacent end of the other outermost element otr eaoh group, means forming passageways between alternate ends of elements of each group so that Ithe elements of each group are connected in series and in a serpentine arrangement that passes evaporating cooling fluid from the intake manif-old to the exhaust manifold and so that the groups are connected in parallel between said manifolds.

10. A tubular element for a horizontal twin contact freezing plate, said ele-ment being adapted to conduct evaporating cooling fluid therethrough in a predetermined direction, said element being of rectangular hollow cross-section and consisting of |horizontal plane upper and lower walls and vertical side walls, said upper and lower walls respectively fonming portions of the upper and lower surfaces of the freezing plate and a diverting means in said element, said diverting means comprising a thin sheet parallel to the upper and lower walls of the tubular element, said sheet being spaced from both said walls and dividing said element into two separate longitudinal chambers, tabs formed from said sheet, each said tab sloping upwardly and in the direction of flow of the cooling lluid from a 'lower end adjacent the lower wall of the tubular element to an upper end integral with the `sheet and defining an opening left by forcing the tab out of the plane ott the sheet whereby cooling duid flowing along the lower wall of the element in the lower chamber is raised by the tabs through the openings in the sheet onto lthe upper surface of the sheet in the upper chamber where Athe iluid ows in contact with the upper wall of the tubular element.

References Cited by the Examiner UNITED STATES PATENTS 2,480,706 8/1949 Brillen 165-179 X 2,538,014 1/1951 Kleist 62--515 X 2,852,042 9/1958 Lynn 165-109 X 3,135,323 6/1964 Kleist 165-175 X FOREIGN PATENTS 481,755 3/1938 Great Britain.

ROBERT A. OLEARY, Primary Examiner. 

1. A HORIZONTAL TWIN CONTACT FREEZING PLATE HAVING AN UPPER CONTINUOUS SURFACE AND A LOWER CONTINUOUS SURFACE, SAD LOWER SURFACE BEING PARALLEL TO AND COEXTENSIVE WITH SAID UPPER SURFACE, SAID PLATE INCLUDING AN INTAKE MANIFOLD FOR ADMITTING COOLING FLUID TO BE EVAPORATED AND AN EXHAUST MANIFOLD, SAID EXHAUST MANIFOLD BEING PARALLEL TO SAID INTAKE MANIFOLD, SEVERAL GROUPS OF PARALLEL TUBULAR ELEMENTS SPANNING THE SPACE BETWEEN THE INTAKE AND EXHAUST MANIFOLDS, EACH TUBULAR ELEMENT BEING OF LIKE RECTANGULAR HOLLOW CROSS-SECTION AND CONSISTING OF HORIZONTAL PANE UPPER AND LOWER WALLS AND VERTCAL SIDE WALLS, THE SIDE WALLS OF ADJACENT ELEMENTS IN EACH GROUP BEING IN ABUTTING INTERSECURED RELATIONSHIP AND THE SIDE WALLS OF THE OUTERMOST ELEMENTS OF ADJACENT GROUPS BEING IN ABUTTING INTERSECURED RELATIONSHIP, THE UPPER WALLS OF ALL THE ELEMENTS LYING IN A SINGLE HORIZONTAL PLANE AND CONSTITUTING THE CONTINUOUS UPPER SURFACE OF THE PLATE, THE LOWER WALLS OF ALL THE ELEMENTS LYING IN ANOTHER SINGLE HORIZONTAL PLANE AND CONSTITUTING THE CONTINUOUS LOWER SURFACE OF THE PLATE, THERE BEING THE SAME ODD NUMBER OF TUBULAR ELEMENTS IN EACH GROUP, MEANS SECURING THE ENDS OF THE TUBULAR ELEMENTS TO THE MANIFOLDS, MEANS FORMING A PASSAGEWAY BETWEEN THE INTAKE MANIFOLD AND THE ADJACENT END OF AN OUTERMOST ELEMENT OF EACH GROUP, MEANS FORMING A PASSAGEWAY BETWEEN THE EXHAUST MANIFOLD AND THE ADJACENT END OF THE OTHER OUTERMOST ELEMENT OF EACH GROUP, MEANS FORMING PASSAGEWAYS BETWEEN ALTERNATE ENDS OF ELEMENTS OF EACH GROUP SO THAT THE ELEMENTS OF EACH GROUP ARE CONNECTED IN SERIES AND IN A SERPENTINE ARRANGEMENT THAT PASSES EVAPORATING COOLING FLUID FROM THE INTAKE MANIFOLD TO THE EXHAUST MANIFOLD AND SO THAT THE GROUPS ARE CONNECTED IN PARALLEL BETWEEN SAID MANIFOLDS, AND WITHIN EACH TUBULAR ELEMENT A DIVERTING MEANS FORCING SOME OF THE EVAPORATING COOLING FLUID THAT FLOWS ALONG THE LOWER WALL OF THE ELEMENT TO BE ELEVATED TO FLOW ALONG THE UPPER WALL OF THE ELEMENT. 